This invention relates generally to endoscopes and more particularly to a means for limiting the amount of tension applied to control wires which are utilized to direct or redirect a probe. Endoscopes are currently known which utilize a set of articulated rings with means for bending or articulating the rings to direct the probe. For that purpose, a pair of control wires is employed to articulate the rings, and motion is produced by applying tension to one of the control wires. Wire tension is typically generated by rotation of a control knob, the motion of which is translated through a mechanism, such as a rack and pinion, to pull on one wire while simultaneously releasing tension or producing slack in a second control wire which rotates the rings in the opposite direction.